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Controlling single-molecule junction conductance by molecular interactions.

Kitaguchi Y, Habuka S, Okuyama H, Hatta S, Aruga T, Frederiksen T, Paulsson M, Ueba H - Sci Rep (2015)

Bottom Line: For the rational design of single-molecular electronic devices, it is essential to understand environmental effects on the electronic properties of a working molecule.The anchoring to the other electrode is kept stable using a chalcogen atom with strong bonding to a Cu(110) substrate.Combined with density functional theory calculations, we clarify the role of the electrostatic field in the environmental effect that influences the molecular level alignment.

View Article: PubMed Central - PubMed

Affiliation: Department of Chemistry, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan.

ABSTRACT
For the rational design of single-molecular electronic devices, it is essential to understand environmental effects on the electronic properties of a working molecule. Here we investigate the impact of molecular interactions on the single-molecule conductance by accurately positioning individual molecules on the electrode. To achieve reproducible and precise conductivity measurements, we utilize relatively weak π-bonding between a phenoxy molecule and a STM-tip to form and cleave one contact to the molecule. The anchoring to the other electrode is kept stable using a chalcogen atom with strong bonding to a Cu(110) substrate. These non-destructive measurements permit us to investigate the variation in single-molecule conductance under different but controlled environmental conditions. Combined with density functional theory calculations, we clarify the role of the electrostatic field in the environmental effect that influences the molecular level alignment.

No MeSH data available.


Related in: MedlinePlus

STM images of phenoxy molecules on Cu(110) and controlled switching of the molecular junction.(a) An STM image of a phenoxy molecule on Cu(110) with schematic illustration. A pair of protrusion and depression associated with the phenyl ring and oxygen atom, respectively. The white grid lines indicate the lattice of Cu(110). The image size is 19 × 24 Å2. (b) The tunnel current during the approach (blue curves) and retraction (red curves) of the tip along the surface normal. The curves were recorded at various lateral positions shown in (a), and vertically offset for clarity. The origin of the abscissa (Δz = 0) is the initial tip height corresponding to V = 50 mV and I = 1 nA over the protrusion. (c) Repeated switching of the molecular junction by using the conductance hysteresis shown in the inset. The tip was positioned at Δz = 1.7 Å (cross in the inset), and then temporally approached and removed out of the hysteresis region, which switches the junction to the ‘on’ (dot) and ‘off’ (cross) states, respectively.
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f1: STM images of phenoxy molecules on Cu(110) and controlled switching of the molecular junction.(a) An STM image of a phenoxy molecule on Cu(110) with schematic illustration. A pair of protrusion and depression associated with the phenyl ring and oxygen atom, respectively. The white grid lines indicate the lattice of Cu(110). The image size is 19 × 24 Å2. (b) The tunnel current during the approach (blue curves) and retraction (red curves) of the tip along the surface normal. The curves were recorded at various lateral positions shown in (a), and vertically offset for clarity. The origin of the abscissa (Δz = 0) is the initial tip height corresponding to V = 50 mV and I = 1 nA over the protrusion. (c) Repeated switching of the molecular junction by using the conductance hysteresis shown in the inset. The tip was positioned at Δz = 1.7 Å (cross in the inset), and then temporally approached and removed out of the hysteresis region, which switches the junction to the ‘on’ (dot) and ‘off’ (cross) states, respectively.

Mentions: The STM image of a phenoxy molecule on Cu(110) shows a pair formed by a protrusion and a smaller depression (Fig. 1a), reflecting the density of states at the phenyl ring and oxygen atom, respectively. The white lines show the lattice of surface Cu atoms, with the crossing points indicating the atomic positions. It was revealed that the molecule is nearly flat on the surface and bonded to the short-bridge site via the oxygen atom26, as schematically shown in the inset to Fig. 1a.


Controlling single-molecule junction conductance by molecular interactions.

Kitaguchi Y, Habuka S, Okuyama H, Hatta S, Aruga T, Frederiksen T, Paulsson M, Ueba H - Sci Rep (2015)

STM images of phenoxy molecules on Cu(110) and controlled switching of the molecular junction.(a) An STM image of a phenoxy molecule on Cu(110) with schematic illustration. A pair of protrusion and depression associated with the phenyl ring and oxygen atom, respectively. The white grid lines indicate the lattice of Cu(110). The image size is 19 × 24 Å2. (b) The tunnel current during the approach (blue curves) and retraction (red curves) of the tip along the surface normal. The curves were recorded at various lateral positions shown in (a), and vertically offset for clarity. The origin of the abscissa (Δz = 0) is the initial tip height corresponding to V = 50 mV and I = 1 nA over the protrusion. (c) Repeated switching of the molecular junction by using the conductance hysteresis shown in the inset. The tip was positioned at Δz = 1.7 Å (cross in the inset), and then temporally approached and removed out of the hysteresis region, which switches the junction to the ‘on’ (dot) and ‘off’ (cross) states, respectively.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4488765&req=5

f1: STM images of phenoxy molecules on Cu(110) and controlled switching of the molecular junction.(a) An STM image of a phenoxy molecule on Cu(110) with schematic illustration. A pair of protrusion and depression associated with the phenyl ring and oxygen atom, respectively. The white grid lines indicate the lattice of Cu(110). The image size is 19 × 24 Å2. (b) The tunnel current during the approach (blue curves) and retraction (red curves) of the tip along the surface normal. The curves were recorded at various lateral positions shown in (a), and vertically offset for clarity. The origin of the abscissa (Δz = 0) is the initial tip height corresponding to V = 50 mV and I = 1 nA over the protrusion. (c) Repeated switching of the molecular junction by using the conductance hysteresis shown in the inset. The tip was positioned at Δz = 1.7 Å (cross in the inset), and then temporally approached and removed out of the hysteresis region, which switches the junction to the ‘on’ (dot) and ‘off’ (cross) states, respectively.
Mentions: The STM image of a phenoxy molecule on Cu(110) shows a pair formed by a protrusion and a smaller depression (Fig. 1a), reflecting the density of states at the phenyl ring and oxygen atom, respectively. The white lines show the lattice of surface Cu atoms, with the crossing points indicating the atomic positions. It was revealed that the molecule is nearly flat on the surface and bonded to the short-bridge site via the oxygen atom26, as schematically shown in the inset to Fig. 1a.

Bottom Line: For the rational design of single-molecular electronic devices, it is essential to understand environmental effects on the electronic properties of a working molecule.The anchoring to the other electrode is kept stable using a chalcogen atom with strong bonding to a Cu(110) substrate.Combined with density functional theory calculations, we clarify the role of the electrostatic field in the environmental effect that influences the molecular level alignment.

View Article: PubMed Central - PubMed

Affiliation: Department of Chemistry, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan.

ABSTRACT
For the rational design of single-molecular electronic devices, it is essential to understand environmental effects on the electronic properties of a working molecule. Here we investigate the impact of molecular interactions on the single-molecule conductance by accurately positioning individual molecules on the electrode. To achieve reproducible and precise conductivity measurements, we utilize relatively weak π-bonding between a phenoxy molecule and a STM-tip to form and cleave one contact to the molecule. The anchoring to the other electrode is kept stable using a chalcogen atom with strong bonding to a Cu(110) substrate. These non-destructive measurements permit us to investigate the variation in single-molecule conductance under different but controlled environmental conditions. Combined with density functional theory calculations, we clarify the role of the electrostatic field in the environmental effect that influences the molecular level alignment.

No MeSH data available.


Related in: MedlinePlus